ช่วยดูให้หน่อยครับ Upload Error หรือว่าแนะนำหน่อยก็ได้ครับ ขอบคุณครับ

<?php
	for($i=0;$i<count($_FILES["filUpload"]["name"]);$i++)
	{
		if($_FILES["filUpload"]["name"][$i] != "")
		{
			$filUpload=$_FILES['filUpload']['tmp_name'][$i];
			$filUpload_name=$_FILES['filUpload']['name'][$i];
			$filUpload_size=$_FILES['filUpload']['size'][$i];
			$filUpload_type=$_FILES['filUpload']['type'][$i];

			$ext = strtolower(end(explode('.', $filUpload_name)));

			if ($ext == "jpg" or $ext == "jpeg" or $ext =="png" or $ext=="gif") {

			// หา id_slider ที่มากที่สุดของ slider
			$sql="select max(id_slider) from slider";
			$result=mysql_db_query($dbname,$sql);
			$r=mysql_fetch_array($result);
			$id_max=$r[0];

			$filename=$id_max.".".$ext;

			copy($filUpload,"../images/slider/$filename");
		
			if ($ext =="jpg" or $ext =="jpeg") {
				$ori_img = imagecreatefromjpeg($filename);
			} else if ($ext =="png") {
				$ori_img = imagecreatefrompng($filename);
			} else if ($ext =="gif") {
				$ori_img = imagecreatefromgif($filename);
			}
			$ori_size = getimagesize($filename);
			$ori_w = $ori_size[0];
			$ori_h = $ori_size[1];

			$new_w = 480; 
			$new_h = 220;

			$new_img= imagecreatetruecolor($new_w, $new_h);
			imagecopyresized($new_img,$ori_img,0,0,0,0,$new_w, $new_h,$ori_w,$ori_h);
	
			if ($ext =="jpg" or $ext =="jpeg") {
			imagejpeg($new_img,"../images/slider/$filename");
			} else if ($ext =="png") {
			imagepng($new_img,"../images/slider/$filename");
			} else if ($ext =="gif") {
			imagegif($new_img,"../images/slider/$filename");
			}

			imagedestroy($ori_img); 
			imagedestroy($new_img); 

			$sql="insert into slider value('','$filename')";
			$result=mysql_db_query($dbname,$sql);
			}
		}
	}
	echo "<script>alert(' เพิ่มข้อมูลเรียบร้อยแล้ว ');</script>"; 
	echo "<META HTTP-EQUIV=\"Refresh\" CONTENT=\"0.1;URL=slider.php\">"; exit();
?>